right. My car is having this horrible 3500 rpm hesitation issue. Its an 86 NA. All emissions stuff has been removed by the previous owner. Ive recently done these things...



Fuel filter

Air filter

Checked and cleaned all the grounds on the engine harness.

Added new grounds for the coils.

Cleaned and added grounds to the ecu.

Ground that atmosphere pressure thing in the engine bay.



The problem is still there. Its really pissing me off. Does anyone have any other ideas on what might be causing this stupid issue to still be here?



Here is some back story stuffs that might be useful to someone.

When I first bought the car it had this issue. I searched on this forum and found that I should add some new grounds and clean the existing ones. I did that and the problem went away. About 3 months ago I had a fuel leak so I fixed that and replaced this one fuel line that went from the primary rail to the secondary rail. 1 month later the fuel leak returned. But it was the fuel line I replaced. I had this one shop near me fix the leak and ever since then its been acting all stupid with this hesitation issue.

could be your secondary fuel injectors are coming on too rich and early. spark plugs?

how could the secondary injectors come on early? i replaced the plugs and wires about 5k miles ago.

check and make sure the grounds and actually attached right since the shop might have knocks some off and never noticed them

Check the location and condition of the Starter Ground I had the same issue i did Aaron cakes Ground rework and found my Starter Ground was moved to the wrong Location and was Dirty as Hell

GROUNDS, GROUNDS and more GROUNDS.....

I'm surprised if you've cleaned and checked all grounds AND added grounds to the ECU. Grounding the ECU always worked for me on S4 NA's. Honestly I'd check them again. Once after having a slow coolant leak, my freshly cleaned grounds started to corrode due to moisture under the hood.

Check the ECU Ground on the top of the Engine under the intake Manifold when they did the fuel leak they may have not put it back right